Abstract
We nade observations of the atmospheric nuclei at the sea coast near Sendai and found that these nuclei contain sea-salt and that their size distribution is expressed by the simple formula n0r03=C, where n0Δr0 is the number of sea-salt nuclei which are contained in 1cc of the atmosphere and whose radii range from(r0-Δr0/2) to (r0+Δr0/2) and C is expressed by C=2.2W×102, where W is the amount of sea-salt in 1cc of the atmosphere.
The variation of the relative humidity H in equilibrium with the sea-salt srop is wxpressed by the empirical formula H=1-0.52c, where c is the ratio of the weight of dissolved sea-salt to that of water in the sea-salt drop.
By using the above two formulae we obtained a new formula expressing the opacity Χ in terms of relative humidity over the sea surface except near the industrial area. This formula is given by
whrer Χp is the opacity due to non-hygroscopic particles, ρ0 the density of sea-salt and A is a numerical factor (about 9.5) depending on the wave length of light.
Furthermore it was found that by inserting reasonable values for C and χp the result of observation at Valentia can be explained well by the above formula.
